This invention relates to miniaturized drug delivery devices and more particularly, to controlled time and rate release multi-welled drug delivery devices.
Drug delivery is an important aspect of medical treatment. The efficacy of many drugs is directly related to the way in which they are administered. Some therapies require that the drug be repeatedly administered to the patient over a long period of time. This makes the selection of a proper drug delivery method problematic. Patients often forget, are unwilling, or are unable to take their medication. Drug delivery also becomes problematic when the drugs are too potent for systemic delivery. Therefore, attempts have been made to design and fabricate a delivery device which is capable of the controlled, pulsatile or continuous release of a wide variety of molecules including, but not limited to, drugs and other therapeutics.
Controlled release polymeric devices have been designed to provide drug release over a period of time via diffusion of the drug out of the polymer and/or degradation of the polymer over the desired time period following administration to the patient. However, these devices are relatively simple.
U.S. Pat. No. 5,490,962 to Cima, et al. discloses the use of three dimensional printing methods to make more complex devices which provide release over a desired time frame, of one or more drugs. Although the general procedure for making a complex device is described, specific designs are not detailed.
U.S. Pat. No. 4,003,379 to Ellinwood describes an implantable electromechanically driven device that includes a flexible retractable walled container, which receives medication from a storage area via an inlet and then dispenses the medication into the body via an outlet. U.S. Pat. No. 4,146,029 and U.S. Pat. No. 3,692,027 to Ellinwood disclose self-powered medication systems that have programmable miniaturized dispensing means. U.S. Pat. No. 4,360,019 to Jassawalla discloses an implantable infusion device that includes an actuating means for delivery of the drug through a catheter. The actuating means includes a solenoid driven miniature pump. All of these devices include miniature power-driven mechanical parts that are required to operate in the body, i.e., they must retract, dispense, or pump. These are complicated and subject to breakdown. Moreover, due to complexity and size restrictions, they are unsuitable to deliver more than a few drugs or drug mixtures at a time.
Co-pending application U.S. Ser. No. 08/675,375, filed Jul. 2, 1996, discloses microchip devices for delivery of molecules, such as drugs. These devices typically include hundreds to thousands of reservoirs, or wells, containing the molecules and a release system that controls the rate of release of the molecules. For example, the reservoirs may have caps made of a material that degrades at a known rate or that has a known permeability (passive release). Alternately, the caps may include a conductive material capable of dissolving upon application of an electrical potential (active release).
It is therefore an object of the present invention to provide a method to manufacture a dependable, multi-welled delivery device for drugs and other molecules which can operate for weeks or years at a time.
It is another object of the present invention to provide a method to make a device that allows delivery of drugs or other molecules in either a pulsatile or continuous manner.
It is yet another object of the present invention to provide a method to make a device that allows the delivery to be controlled either passively or actively.
It is also an object of the present invention to provide a method to make a device that can hold many different drugs or other molecules of varying dosages and is small enough to be implanted, injected or swallowed, if desired.